The invention relates to transmission arrangements for motor vehicles in which engine torque is converted into a wheel axle torque and engine speed into a wheel axle speed and shift steps, torque converters, planetary gear sets, torsional vibration dampers, clutches and electric machines may be provided in the drive train.
Six and seven gear Lepelletier automatic transmission structures (six or seven forward gears and a single reverse gear) are known which are basically a particular combination of a simple planetary gear set with a Ravigneaux gear set. Ravigneau gear sets are well known gear sets that are used in 4-speed transmission blocks, i.e., four forward gear ratios and a single reverse gear. A known six gear Lepelletier automatic transmission is illustrated in FIG. 1. Disposed in converter W, characterized by its main components pump P, turbine T and stator L, is a converter lockup clutch WK. The gear set comprises a planetary stage on the input side (3-shaft crank mechanism) and a Ravigneaux set (4-shaft crank mechanism) on the output side. Disposed between them are five wet-running clutches or brakes. FIG. 1 corresponds to the prior art of using wet, i.e., hydraulic, clutches and brakes.